feature(mapper): Add logic for instanced areas (#46)

* Adds logic for instanced areas

Calls to deleteArea when switching to a new zone if that zone is "instanced".  There may be instances where this is incorrect, but I haven't run into any since adding the logic for ignoring "Battlefield".

* Handle case where map.prev_info.area is not yet set

This likely would have led to the deletion of the area a user logged into.

Author: eterchun

prs-mapper.lua

@@ -328,6 +328,7 @@ end
 
 function map.eventHandler(event,...)
     if event == "gmcp.room.info" then
+	if gmcp.room.info.zone == "Battlefield" then return end
         map.prev_info = map.room_info
         map.room_info = {
           vnum = gmcp.room.info.num,
@@ -341,6 +342,11 @@ function map.eventHandler(event,...)
         for k,v in pairs(map.room_info.exits) do
             map.room_info.exits[k] = tonumber(v)
         end
+        if map.prev_info.area and (map.prev_info.area ~= map.room_info.area) then
+          if gmcp.room.info.instanced then
+            deleteArea(gmcp.room.info.zone)
+          end
+        end
         handle_move()
     elseif event == "shiftRoom" then
         local dir = exitmap[arg[1]] or arg[1]